1. Field of the Invention
The present invention relates to a seal structure in an engine body, including a crankcase which has a crank chamber and which is coupled to a lower end face of a cylinder block having a cylinder bore, the crankcase being comprised of first and second case halves coupled to each other in a plane perpendicular to joint surfaces of the cylinder block and the crankcase. The seal structure is designed so that the joint surfaces of the cylinder block and the crank case are sealed to prevent the leakage of pressure and oil from the crank chamber.
2. Description of the Related Art
A structure of an engine body as described above is already known, for example, as disclosed in Japanese Patent Application Laid-open No. 9-177528. In this engine body, a liquid packing is applied to the joint surfaces of the cylinder block and the crankcase and to joint surfaces of the first and second case halves constituting the crankcase, to thereby seal these joint surfaces.
In the conventionally known seal structure, in order to ensure a good sealability of the liquid packing, it is necessary to control the pressure of coupling between the joint surfaces of the cylinder head and the crankcase and that between the joint surfaces of the first and second case halves, so that skill is required to assemble the engine body.